/Engine/Source/Runtime/EyeTracker/Public/IEyeTracker.h
Specifies player being eye-tracked. This is not necessary for all devices, but is necessary for some to determine viewport properties, etc.. Implementing class should cache this locally as it doesn't need to be called every tick.
void SetEyeTrackedPlayer ( [APlayerController](API\Runtime\Engine\GameFramework\APlayerController) * PlayerController )